Deserts are not the only otherwordly places on Earth. Astronauts can train for space missions in underwater environments like the enormous Neutral Buoyancy Laboratory, located in NASA's Johnson Space Center. But these huge bathtubs do not always accurately simulate the trials of space missions: for instance, astronauts can't live in modules at the bottom of these tubs for days on end. That's when NASA turns to the Aquarius Underwater Laboratory. Located 60 feet below the surface of the Atlantic Ocean near Key Largo, it lets spacewalkers work with support crews and a mission control. These particular astronauts are participating in NEEMO 15, the latest NASA Extreme Environment Mission Operations voyage; they are helping NASA determine the best way to send a manned crew to an asteroid.